The main goal for the second year will be to solve the problem of superposition. We will pursue the basic strategy outlined in the original proposal which is a straightforward development of our approach to resolving unitary spikes. This approach is based on 2 recording channels along a nerve or connective which allows us to use a clustering algorithm to separate out unitary spikes on the basis of peak-to-peak amplitude and conduction velocity. Once all unitary spikes in a sample are clustered, then the remaining (unclustered) spikes are primarily compound waveforms due to simultaneous firing of 2 or more units. If more than 1 unit is firing then additional inflections should appear in the proximal and/or distal waveforms. Using the interactive graphics display terminal we will identify all inflections on both channels and then look for all possible offsets between channels. Some of these offsets should agree precisely with offsets of previously clustered units from the same sample. The average waveforms on two channels will be aligned with the appropriate inflections and subtracted out. The underlying waveform should then be unitary (if only 2 units were firing to begin with). This part will be tested extensively using the 2 giant axons discussed above. Although this procedure will be laborious to do interactively, we hope to be able to automate it and thereby significantly speed up the data processing. If this approach proves feasible, then this will bring us a long way toward our goal of understanding central pattern generation in large neuronal populations.